Alloy



Patented Aug. 16, 1938 v 2,127,245

UNITED STATES PATENT OFFICE 2,127,205 ALLOY Walter R. Breeler, Troy, N. Y., aslignor to Ludlum Steel 00., Watervliet, N. Y, a corporation of New Jersey No Drawing. Application July 19, 1935,

Serial No. 32,237

6 Claims. (Cl. 75-124) My invention relates to alloy steels and paras will be apparent from the following comticularly to steels having high resistance to hot parative tests of two alloys both of which conoxldation, scaling, and corrosive .loss by the attain chromium and manganese in about the tack of compounds containing lead at high temsame amounts but in one of which the aluminum .1 peratures. The alloy is particularly adapted for content is 3.1% with a silicon content of 0.6%. use in lead pots, pyrometer tubes and the like, and in the other alloy no aluminum is present.

and for exhaust valves, seat inserts and other but the silicon content is 2.8%. parts of internal combustion engines which are subjected to contact with hot exhaust gases re- Lossinweight(mg./sq.em.lmin.) sulting from the combustion of gasoline contalning lead anti-knock compounds. The alloys 0 Si Cr Ai Mu Roch shorter, who

at present employed for these purposes are rather well 38, 2P pi high priced, and one of the objects of my invention is to produce a relatively cheap material characterized by its resistance to hot oxidation 0,3 and to hot lead compounds.

v The essential ingredients of my alloy and the limits between which they are employed are as Neither 01' these alloys shows any loss in weight as 20.4 8.9 0.0 20.8 3.1 an 21 Nil Nil us 0.6

follows: when subjected to lead oxy bromide at 1350 F. 20 Percent At 1580 F. the alloy without the aluminum shows 0 .05 to 3 a rather substantial loss while the other shows Mn 2.00 to 20 none. At 1800 F. the alloy without the aluminum Cr. more than 5.00 to but with fairly high silicon when subjected to Al .50 to 15 lead oxide shows a loss exceeding three times 35 Fe 26, to 92 that of the other, and at the same temperature with a mixture of lead oxide and lead sulphate the loss 0! the composition without the aluminum is about seventy times greater than the other.

A preferred range of the above alloying elements is as follows:

80 C 52 g? In the preferred analysis range mentioned, 3 'g'i": 8'01; 0 and in the lower ranges of aluminum, chroto mium and manganese (especially aluminum), the to alloy is readily iorgeable and rollable. In the higher ranges of alloy content (especially alumi- While the foregoing are the only elements necnuin) the alloy is more diiilcult to hot work essary to attain the objects of my invention, and requires more care at this operation. Howother elements, in quantities which do not apever, in cases where not working is impractical, preciably affect the basic characteristics of the the alloy may be readily east and used in this alloy, namely, resistance to hot oxidation and to fo mlead compounds at high temperatures, may be y alloy an be mad y a y f t l kn wn incorporated if desired. Such elements as selemethod-S melting,- 6x81111116. when 18 nium, tellurium, phosphorus and sulphur, in an electric arc furnace the aluminum may be quantities up to 0.30% will improve the maadded as metallic aluminum or aluminum alloy chineability of the alloy, and nitrogen in quan- 1n the furnace itself. the aluminum 811 titl u t 0.3% will increase t strength at aluminum alloy maybeadded in the ladle. These heat and also the hardness. additions are preferably made under protective Silicon, of course is always present in steels slag coatings of suc 8 a ure that y will not and irons, and. while I prefer to keep the silicon react detrimentally with the aluminum steel and under about 1%, the quantity in any case should they should be of such composition as to dissolve be less than the aluminum content. I find that or flux any undesirable oxides such as A1203. silicon in excess of the aluminum very greatly Instead of theelectric arc furnace, induction reduces the resistance of the alloy to corrosive furnaces may be used. Such equipment may or loss when subjected to attack by lead containmay not be used with controlled atmospheres. ing compounds at high temperature. Silicon and What I claim is:

15 aluminum are not interchangeable in the alloy 1. A readily rorgeable alloy steel containing a all iron; the aluminum content being in excess resistance to hot oxidation and corrosive loss when subjected to attack by lead containing compounds at temperatures of the order of the operating temperatures of exhaust valves in internal combustion engines; the only essentialelements necessary to obtain such characteristics being carbon from 0.2% to 1%, manganese from 8% to 12%, chromium from 18% to 22%, aluminum from 1.5% to 3.5% with the balance substantially of the siliconcontent. it any, in said steel.

2. An internal combustion engine valve characterized by its high resistance to hot oxidation and corrosive loss when subjected to attack by lead containing compounds at temperatures of the order of the operating temperatures ofexhaust valves in internal combustion engines; said valve comprising an alloy steel containing a plurality of'elements of which the only essential elements necessary to obtain the foregoing characteristics are carbon from 0.05% to 3%, manganese from 2% to 20%, chromium from more than 5% to 35% and aluminum from 0.5% to 15%, with the balance substantially all iron; the

aluminum content being in excess of the silicon content, it any, in said steel. 1

3. An internal combustion engine v'alve characterized by its high resistance to hot oxidation and corrosive loss when subjected to attack by lead containing compounds at temperatures of the order of the operating temperatures of exhaust valves in internal combustion engines; said valve comprising a readily forgeable alloy steel containing a plurality of elements of which the only essential elements necessary to obtain the foregoing characteristics are carbon 0.2% to 1%,

manganese 8% to 12%, chromium 18% to 22%, and aluminum from 1.5% m 3.5%, with the balance substantially all iron; the aluminum content being in excess of the-silicon content, if any, in said steel. a

4. A readily forgeable alloy steel containing a plurality of elements and characterized by its high resistance to hot oxidation and corrosive lossrwhen subjected to attack by lead containing compounds at temperatures of the order of the operating temperatures of exhaust valves in internal combustion engines; the only essential elements-necessary to obtain such characteristics being carbon from 0.2% to 1%, manganese from 8% to 12%, chromium from 18%, to 22%, and aluminum from 1.5% to 3.5% with' the balance substantially all iron; the silicon content being less than 1% and less than the aluminum content.

5. An internal combustion engine valve comprising the alloy of claim 4. v r

. 6. An internal combustion engine valve characterized by its high resistance to hot oxidation and corrosive loss when subjected to attack by lead containing compounds at temperatures of the order of the operating temperatures ofexhaust valves in internal combustion engines; said valve comprising an alloy steel containing a plurality of elements of which the only essential elements necessary to obtain the foregoing characteristics are carbon from 0.05% to 3%, manganese from 2% to 20%, chromium from more than 5% to and aluminum from 0.5% to 15%, with the balance substantially all iron; the

*' silicon content being less than 1%, and less than the aluminum content. 

